battery inverter setup

[jabingham81]

So i have looked around and i guess i just dont get it and need someone to spell it out for me. What i need to have a battery inverter setup to power a small tv/dvd player/ and mini fridge (3 cu/ft) in a van. It would need to power these for maybe 2 full days max. What battery? What inverter? Do i wire it in series with the vehicle or do it stand alone? Please help educate me.

[madjack]

...the inverter will be hooked up in parallel to the battery...you will need to know the wattage needed for the fridge/lights...keep in mind, there is a 10 fold increase in the AMPERAGE supplied from the battery to match the wattage needed to run the fridge on AC power...for example, if the fridge and other appliance needed 5-10AMPS of 120vac power, the battery will need to supply 50-100AMPS per hour of 12vdc power to supply your needs...since your battery will only supply around 5O(orso)AMPS/hour, you will kill your battery after about an hour of actual run time...you need to rethink this since it is not feasible under the circumstance you have stated...................
madjack

p.s the above info is just real basic but will give you and idea of what will be needed..........

[48Rob]

Jack is correct if you are camping without running the charging system on the van.

If you are doing a cross country trip driving most of the day, the system could work, but you would need to freeze blocks of ice during the time the van is charging the battery to keep the inverter running, then unplug the fridge at night to save the battery.
The setup with a decent sized battery would be able to power the lights and television/dvd when you stopped for the night.

Pulling that much power, you'll want a separate battery to power the inverter, with an isolator to prevent the van battery from being drained.


Rob

[jabingham81]

so even though it will use .75amps and will not be continually running ( i would imagine it would turn on once or twice a hour) it wont work? So i guess a yamaha or honda generator needs to be ordered.

[madjack]

.75amp seems light for a usage number BUT lets work with it...that .75a @120vac will need 7.5a @12vdc power...we will round up to 10a @12dc to account for other usages/inefficiencies...this means, if you have a 100amp/hour battery(separate from vehicle) AND considering a battery should not be discharged below 50% for longevity purposes, this leaves you with 50amp/hours of usable 12vdc power or about 5 hours of usable power...now assume a duty cycle of 30%-50%, this will give you a run time of 10-15 hours before a recharge is needed...somewhat short of the 2+days of power needed...a small gennie(under 1000watts) can be bought for simple charging needs or a larger gennie(2000+watts) to be used for more stringent power needs................
madjack

[Big Dan]

You have a tv, a frige and other thing you need power for. Its not impossible to power these things for a weekend or longer. You just need the right system. here is a link you can look at to help you understand what you might need. http://handybobsolar.wordpress.com/the-rv-battery-charging-puzzle-2/ You need to figure out how much power you need and build a system that will accommodate your needs. You might need more information than whats in this link but its a start. good luck.